A hollow modular building block made of concrete has being known and used in the American construction industry since the beginning of the 20th century. This technology is still extensively used till the present time, and a great variety of standardized hollow modular building blocks are available on the market. See, e.g., U.S. Pat. No. 6,088,987 issued in 2000 to Simmons, et al., U.S. Pat. No. 5,822,922 issued in 1998 to Haener, etc. An example of a typical known hollow modular concrete block is shown in FIG. 1. It can be seen from this drawing that the block 20 comprises a molded concrete body 22 with two through openings 24, 26 with a separating wall 28 between the openings. For technological purposes the openings may have tapered surfaces. FIG. 2 is a three-dimensional view of a part of a wall 30 assembled from the hollow modular building blocks 32, 33, 34, 35 of the type shown in FIG. 1. The blocks are bonded to each other by seams 36, 37, 38, 39, 40, 41, and 42 of a binding material such as mortar.
The main disadvantage of the existing hollow modular building block shown in FIGS. 1 and 2 is that in a construction element assembled from such blocks the load-carrying function is fulfilled by the blocks themselves. Therefore they have to be made of a sufficiently strong and durable material which always be maintained under loading conditions. For the above reason, the existing blocks of the aforementioned type are produced from special grades of concrete, which makes the structural element heavy in weight and expensive to manufacture.
In order to solve the problem of strength and durability, the hollows 44, 46, 48, 50 (FIG. 2) can be filled with a mortar. FIG. 3 illustrates a cross section of a part of a construction element 52 assembled from the hollow modular blocks 54 and 56 filled with concrete 53. Such a construction becomes much heavier and more expensive than the one shown in FIG. 2, since it consumes more material.
Another disadvantage of both structures shown in FIGS. 2 and 3 is a provision of so called “bridges of cold” which impart to the blocks as well as to the construction elements assembled from the blocks heat- and cold-conductive properties. More specifically, partitions 45 and 49 between the openings 44, 46 and 48, 50, respectively, as well as a partition 51 between the blocks 32 and 34 interconnect the outer and inner surfaces of the blocks and construction elements. This means that the wall made of the hollow modular blocks of the type shown in FIG. 1 will conduct heat/cold between the inner and outer surfaces. In the construction shown in FIG. 3, the heat/cold conducting problems become even more aggravated since the “bridge of cold” is distributed over the entire cross-section of each block. Therefore, additional heat-insulating elements, such as thermoinsulating layers, must be incorporated into the construction of structural elements, if heat-insulating properties are critical.
Still another disadvantage of the existing modular hollow concrete block is that the load-carrying function of a load-carrying element cannot be easily combined with architectural functions such as texture, color, hiding of connection seams, decorative properties of the internal and external surfaces, etc. Therefore, for acquiring the aforementioned additional properties, the surfaces of the construction elements, such as walls, assembled from the existing modular hollow blocks must be coated with additional facing or decorative panels.
It is also known to build insulated concrete wall structures by using a plurality of modules stacked together to provide a concrete form which can subsequently be filled with cementation material and thereby provide a unitary concrete wall structure. U.S. Pat. No. 4,223,501 issued to DeLozier in 1980 teaches the use of such a module for the fabrication of a concrete monolithic wall structure having foam insulation permanently attached to the structure and forming the inner and outer wall surfaces. The main advantages of this method of building is that the concrete forms remain in place as a useful component of the wall structure.
When a plurality of the prior art modules are assembled into a concrete building form, the sides of the module often are of inadequate strength to provide the necessary support required to contain the wet cement until it can “set” and thereby become a self supporting monolithic concrete wall of an enclosure. Lateral movement of the module walls results in an unsightly and unacceptable wall surface, accordingly, it is absolutely necessary that something be done to increase the wall strength to where there is no doubt that the module walls will resist lateral movement occasioned by the hydrostatic head of the wet concrete. Consequently, it is common practice to augment the strength of the module by employing extraneous timbers assembled into a lattice work and tied against the module walls to help contain the wet cement until it can “set”.
For this and other reasons, many skilled in the art prefer the old technique of building concrete forms made of 2×4 timbers and plywood tied together in a manner to provide a structure that adequately resists the hydrostatic pressure of the concrete, rather than utilize the more modem and cost effective foam plastic module.
An attempt has been made to solve the problem of the concrete form described in U.S. Pat. No. 4,223,501. For example, U.S. Pat. No. 5,596,855 issued to Batch in 1997 provides improvements in foam plastic modules for use in building construction that overcomes the above disadvantages of lateral movement of the module walls and eliminates the need for the extraneous timbers. This is achieved by the provision of a special tension member imbedded within the foam plastic in a manner that secures the opposed wall structure together and thereby resists lateral movement thereof. After the wet concrete has set, the tension members provide a support for subsequent attachment of paneling and other decorative material that may be employed on the inner and outer wall surfaces of the structure.
A disadvantage of the structure of U.S. Pat. No. 5,596,855 consists in that it consumes a significant amount of material, such as cement, for the formation of a load-carrying part of the structural element or building. This is because the aforementioned load-carrying part comprises a monolithic molded body. Another disadvantage of the construction of U.S. Pat. No. 5,596,855 is that it requires the use of spaced tension members inside the interior cavity of the form for connecting the inner and outer walls of the structure as a means for resisting lateral deformations of the walls during the concrete setting period. In other words, during setting of the concrete that forms a monolithic load-carrying structure inside the wall, the inner and outer foam plastic panels are subjected to the action of lateral forces